Process for manufacture of dixanthogen



Patented Nov. 9, 1926.

UNITED STATES WILHELM HIRSCHKIND, OF A NTIOCH, CALIFORNIA;-ASSIGNOR'TO GREAT WESTERN ELECTRO-CHEMICALCOMPAN Y, OF SAN FBAIFCISCO, CALIFORNIA, A CORPORATION OF CALIFORNIA.

PROCECS FOR MANUFACTURE OF DIXANTHOGEN.

No Drawing. Application filed May 24,

This invention relates to the production ofdi-xanthogen, a compound produced from alkali metal' xanthate by the use of various oxidizing agents, such as iodine chlorine, or c'upric salts. Electrolytic oxidation may also be used for the production of the material. The latter method has advantages over the others for the reason hat no deleterious chemicals are used in the process and therefore no impurities are found in the product which necessitate additional treatment for their removal.

I have also discovered that di-xanthogen can be produced by an electrolytic oxida- 1 'tion process with only alcohol and carbon bisul hide as the raw materials.

Alkali metal xanthate, as a commercial product, is the result of a reaction between alcohol, carbon bisulphide' and an alkali 90 metal hydroxide, a solution thereof in water containing none of these compounds in a free state. Dixanthogen contains no alkali metal but otherwise the identical constituents of alkali metal xanthate.

When an aqueous solution of alkali metal xanthate is electrolyzed, the alkali metal is split off and reacts with the water present to form an alkali'metal hydroxide, with the result that as the electrolysis proceeds, the

- concentration of the alkali metal xanthate becomes lower while the concentration of the alkali metal hydroxide rises, the die xanthogen formed dropping out of the solution as an oily material heavier than said solution.

In practice the electrolysis is carried to an economic point of concentration, both ways, fixed by local conditions such as power, cost and so forth,- after which the 4 alkali metal xanthate content brought to the original percentage by the *addition to the solution in proper quantity of the other two constituents of the alkali metal xanthate, that is alcohol and carbon bisulphide, the alkali metal hydroxide being present in the spent solution- The reactions are cyclic in that at one stage the alkali metal hydroxide reacts with alcohol and carbon bisulphide to produce alkali metal xanthate, after which the electrolysis produces the dixanthogen and alkali metal hydroxide to be again followed by the production of more alkali metal xanthate, the only cycle repeated.

, and

thogen crystallizes in the is again 1926. Serial No. 111;379.

tion is then electrolyzed at about three volts with suitable electrodes of lead or platinum, until approximately 25 to 30% of the alkali metal xanthate present has been converted into dixanthogen, which action at the same timev liberates an equivalent amount ofthe caustic alkali in the solution. The apparatus may be arranged for the electrolytic cell to operate continuously or to operate intermittently, as may be desired, but in any event, when the concentration of the caustic alkali in the the desired oint, alcohol and carbon bisulphide are added tothe solution and the solution is allowed .to stand vwith sutficient agitation until the reaction has been completed to bring the quantity of alkali metal xanthate up to the amount originally present in the solution. The solution may then be returned to the electrolytic cell and the The dixanthogen is'a heavy, oily liquid when produced will separate from the solution and may be drawn out of the bottom of the electrolytic cell into suitable containers from time to time. The dixancontainers, its melting point being about twenty-eight derees centigrade. The limit ordinarily set solution has reached for the electrolysis is 20 to 30% of the alkali metal xanthate ori inally present in the solution, but this limit may be changed to give the most effective results under given conditions.

Having thus described my invention, what I desire to secure by Letters Patent of the United States is as follows, but modifications may be made in carrying out the invention and in the above particularly described form thereof, within the purview of the annexed claims.

1. A method of producing dixanthogen which consists in the electrolysis of a solution containing alkali metal xanthate until a portion of the xanthate present has been converted into dixanthogen, adding alcohol and carbon bisulphide to the solution causing it to react until substantially all of the free alkali has been absorbed, and then repeating the electrolysis.

2. A method of producing dixanthogen by electrolysis, which consists of electro lyzing an alkali metal Xanthate solution until a given amount of free alkali is present, dis continuing the electrolysis, adding alcohol and carbon bisulphide and causing them to react with the free alkalito produce a substantial quantity of alkali metal xanthate and thereafter repeating the electrolysis.

3. A method of producing dixanthogen by the electrolysis of alkali metal Xanthate solutionsof suitable strength which consisits in eleetrolyzing a suitable solution containing about 410% alkali metal xanthate until a given amount of the alkali metal xanthate has been converted into dixanthogen, .discontinuing the electrolysis, adding alcohol and carbon bisulphide to the solution in suflicient quantity to react with the free vcaustic present causing the reaction thereof to produce alkali metal xanthate, and thereafter againelectrolyzing the solution to produce repeated quantities of the dixanthogen.

4. The method of producing dixanthogen which comprises the oxidation of alkali metal Xanthate in aqueous solution followed by the addition to said solution of alcohol and carbon bisulphide, from which more alkalimetalxanthatewill be produced for the cyclic production of more dix'anthogen.

5. The method of producing dixanthogen neoame which comprises the oxidation of alkali mental xanthate in aqueous solution with the corresponding production of alkali metal hydroxide followed by the addition of the necessary constituents to said solution to produce more alkali metal Xanthate.

6. The method of producing dixanthogen which comprises the oxidation of alkali metal xanthate in aqueous solution electrolyzing the said solution for the production of dixanthogen, thereafter adding alcohol and carbon bisulphide to produce more alkali metal xanthate, and thereafter again electrolyzing the solution for the production of additional quantities of the dixanthogen,

7. The method of producing dixanthogen which comprises electrolyzing. alkali metal xanthate, thereafter adding the necessary constituents to produce additional alkali metal xanthate, followed by an additional and free alkali metal hydroxide in solution.

In testimony whereof I have hereunto set my hand this llth. day of May A; D. 1826.

i i t HELM ,HIRSCHKIND. 

